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A simple preparative approach to a series of functionalized dimethylphosphinoyl-containing cyclopropanes and cyclobutanes has been developed; it is based on cyclocondensation of dimethylphosphinoyl acetonitrile with 1,2- and 1,3-dibromoalkanes. Synthetic procedures for obtaining nitriles, amines and carboxylic acids containing in their structure small saturated cyclic rings of cyclopropane or cyclobutane and a dimethylphosphine oxide fragment, which are popular in drug design, have been developed.

A novel Gilman-Speeter synthesis of β-lactams has been developed that was rendered highly enantioselective by virtue of isothiourea catalyst’s nucleophilicity. This process depends upon the HATU conversion of carboxylic acids to activated esters which then undergo attack by the homochiral catalyst and subsequently deprotonated by inorganic base to furnish catalytic quantities of the corresponding enolate ions that react with imines to provide the requisite β-lactams in good yields and enantiomeric excesses.

Objectives. Due to their structures, pentaerythritol esters have a number of appealing properties such as high viscosity index when used as oils and excellent compatibility with polyvinyl chloride when used as plasticizers. For the production of pentaerythritol and carboxylic acids, natural gas can be used as a feedstock, which implies a strategic development of the petrochemical industry, a decrease in the amount of gas used for combustion, and its applications for the production of chemical products.Methods. The synthesis process was conducted in a self-catalysis mode with excess acids in a molar ratio of 8:1 and in the presence of a solvent (toluene) of ~30% per reaction mass. This ensures a uniform distillation of the reaction water at a constant temperature of 100–110 °C, a decrease in the side reaction products, and an increase in process selectivity. The products from the reaction mass were isolated by vacuum distillation, and identification of all the synthesized tetraesters was performed by chromatography–mass spectrometry analysis.Results. This work proposes options for optimizing the conditions of the thermal esterification of pentaerythritol with isomeric monocarboxylic acids (isobutyric, isovaleric, pivalic, and 2-ethylhexanoic acids) that have different reactivities due to their structures. Methods for isolating tetraesters of pentaerythritol and corresponding acids have been developed. The characteristics of the main series of ions of tetraesters of pentaerythritol and aliphatic isomeric acids C4–C8 in the mass spectra were obtained.Conclusions. The yields of tetraesters were at 95%–96% of the theoretical value, and product purity was >99.6%. The resulting target products (tetraesters) were characterized by relative color stability, where the maximum degree of color after cleaning was less than 20 units according to Hazen (180 units for tetra-2-ethylhexnoate), which corresponds to the standards in GOST 29131-91 (ISO 2211-73). The esterification rates were compared, and it was shown that the quantitative yields of isomeric tetraesters at 100–110 °C were achieved in 12–15 h for isobutyric and isovaleric acids, 25–27 h for 2-ethyl-hexanoic acid, and ~40 h for pivalic acid.

Corn starch film samples cross-linked using malic, malonic, and succinic acids, and thermoplastic starch were characterized and tested for their water absorption, surface morphology, structural change, and thermomechanical properties. The acids vary in acidity, number of hydroxyl groups, and carbon chain length. The presence of an additional hydroxyl group has helped malic acid form more hydrogen bonding between starch molecules. The relatively higher acidity in malic acid compared to succinic acid is found to be another factor for its better cross-linking potential. The additional carbon chain in succinic acid, which reduces its solubility and acidity; has negatively affected its cross-linking potential. Among the three variables studied, number of hydroxyl group has highly influenced the cross-linking potential, followed by acidity and carbon chain length, respectively. Consequently, the elongation at break and water absorption resistance of thermoplastic starch were improved from 108.63 ​MPa to 175.72 ​MPa and from 140% to 80%, respectively, cross-linking corn starch with malic acid.

In this paper, we present the conditions for modifying the natural clinoptilolite zeolite and giving it catalytic properties by embedding in its structure active centers in the form of metals, such as iron, copper, and cobalt. Clinoptilolite as a catalyst matrix was subjected to ammonium exchange (Me-H-CLI) and hierarchization with hydrochloric acid (Me-da-CLI). Clinoptilolite was also used without modification of its structure (Me-0-CLI). The obtained zeolite catalysts were characterized by means of XRD, BET, DRS UV-VIS and FT-IR analyzes as well as Raman spectroscopy. Zeolite catalysts were used for the conversion of dihydroxyacetone (DHA) based biomass. The catalytic process was carried out by the one-pot method. On the basis of the analysis with the use of high-performance liquid chromatography (HPLC), the reaction products were determined together with their selectivity, yield and also conversion of raw material. During the conversion of DHA, the following organic acids were obtained: lactic acid (LAC), formic acid (FA), pyruvic acid (PAC), acetic acid (AD), and levulinic acid (LA). The highest lactic acid yield (66.2%) was achieved with Co-0-CLI, formic acid (93.6%) with Cu-H-CLI and 87.4% acetic acid with Fe-da-CLI.

The performance of Ti/RuO2IrO2TiO2 anode in the electrochemical conversion of the pollutants contained in the technical liquid of the cashew nutshell waste (t-CNSL) to carboxylic acids (as high added value products) was investigated. The effect of supporting electrolyte and t-CNSL concentrations was studied to determine the best formulation for being electrolyzed with the target of valorization of products. Afterwards, under the optimal formulation conditions, the effect of the applied current density (j) was also evaluated to determine the best operation conditions for producing carboxylic acids. It was observed a selective production of acetic acid as high as 11.7%, which opens the possibility of further studies about the application of the electro-refinery concept for other wastes.

The secondary C(OH)-C bonds are abundant in biomass such as lignin and cellulose. Thus, selective cleavage of the C(OH)-C bonds into value chemicals attracted much attention. Molecular iodine has received considerable attention as an inexpensive and readily available catalyst to yield the corresponding products in excellent yields with high selectivity, but it is highly corrosive and toxic, making its use somewhat unattractive. In this study, I2 was generated in situ from Fe(NO3)3.9H2O/NaI, which was further combined with Fe(NO3)3.9H2O to catalyze the oxidation process. In the reaction, the H2O molecule from the reaction and Fe(NO3)3.9H2O attacked the phenylglyoxal to form benzaldehyde, which was further oxidized to benzoic acid. Aryl primary and secondary benzylic alcohols from lignin were successfully transformed into aryl carboxylic acids by Fe(NO3)3.9H2O/NaI/DMSO. The catalytic system was green and efficient, avoiding the usage of toxic and corrosive molecular I2. From the experiments, it was clear that the yield of the product from the substrates with an electron-donating group was higher than that of electron-withdrawing substituted substrates, which was similar to the aryl secondary alcohols. Aryl alkyl ketones were also successfully conducted by the Fe(NO3)3.9H2O/NaI/DMSO catalytic system.

Abstract Herein we report a conceptually new non‐decarboxylative electrolysis of carboxylic acids to obtain their corresponding anhydrides as highly valuable reagents in organic synthesis. All carbon atoms of the starting material are preserved in the product in an overall redox‐neutral reaction. In a broad substrate scope of carboxylic acids the anhydrides are generated with high selectivity, which demonstrates the versatility of the developed method. Beneficially, no dehydrating reagents are required in comparison to conventional methods and the synthesis is based on uncritical starting materials using graphite and stainless steel as very inexpensive and eco‐friendly electrode materials.

The replacement of a carboxylic acid with a surrogate structure, or (bio)-isostere, is a classical strategy in medicinal chemistry. The general underlying principle is that by maintaining the features of the carboxylic acid critical for biological activity, but appropriately modifying the physicochemical properties, improved analogs may result. In this context, a systematic assessment of the physicochemical properties of carboxylic acid isosteres would be desirable to enable more informed decisions of potential replacements to be used for analog design. Herein we report the structure-property relationships (SPR) of 35 phenylpropionic acid derivatives, in which the carboxylic acid moiety is replaced with a series of known isosteres. The data set generated provides an assessment of the relative impact on the physicochemical properties that these replacements may have compared to the carboxylic acid analog. As such, this study presents a framework for how to rationally apply isosteric replacements of the carboxylic acid functional group.

This study investigates the chemistry and performance of two commercial no-clean fluxes (NCFs) ii.e., NC-1 and NC-2. One water-soluble (WS) flux was also studied for comparison. Chemistry of these fluxes and their residues was studied using the Fourier transmission infrared (FTIR) spectroscopy. Thermal behavior of the flux was evaluated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Hygroscopicity of the residue was determined using water contact angle on residue-contaminated substrates. These fluxes were used to prepare fine pitch ($150~\mu \text{m}$) flip-chip package ($17\times17$ mm2) containing solder bump and copper pillar. Performance of each flux was evaluated using wettability of preprinted SAC-305 solder on copper substrate. Die pull strength of solder bump was evaluated and failure mode was analyzed using scanning electron microscopy (SEM). FTIR results showed that carboxylic acids, tertiary amine, and ether were present in NC-1. Carboxylic acid, secondary amide, and ether were observed in NC-2. WS showed the presence of carboxylic acid, secondary amine, ether, and alcohol. Residue showed the presence of carboxylic acid and amine in NC-1 and only amide in NC-2. Evaporation of certain monocarboxylic acids and ether solvent in NCF led to minimal residue compared to WS. Residue of WS was highly hygroscopic compared to N CF. Wetting of solder bump prepared by using NC-1 and NC-2 was better than WS, which is related to flux chemistry. Consequently, higher die pull strength was observed for N CF. [ABSTRACT FROM AUTHOR]

In this study, the levels of concentration of carboxylic acids (benzoic acid, p-hydroxybenzoic acid, p-hydroxyphenylacetic acid, and hippuric acid) in the urine of autistic children were investigated and compared. The increased excretion of carboxylic acids is related to excessive bacterial activity in the gut, called bacterial overgrowth, which has been related to autism spectrum disorder (ASD) as an impairment in the gut-brain axis. The investigation was based on the analysis of urine samples obtained from 120 ASD children. To identify and quantify urinary carboxylic acids (UCAs), we applied gas chromatography coupled with mass spectrometry (GC-MS). Additionally, we checked the influence of probiotic supplementation, gender, body mass index (BMI) value and age of children on the level of different selected compounds. Most of the obtained results were found within reference ranges. In some cases, the levels of benzoic acid, p-hydroxybenzoic acid, and p-hydroxyphenylacetic acid were particularly elevated. Statistically significant differences were observed in supplementation with probiotics and the level of p-hydroxyphenylacetic acid (p=0.036). The obtained results may indicate disturbances in the intestinal flora in some autistic patients and suggest that supplements may have an influence on the levels of carboxylic acids in urine. Due to the small population of children taking the supplement, further study are needed.

(1-(2,4-Dioxo-1,2,3,4-tetrahydroquinolin-3-yl)-1H-1,2,3-triazol-4-yl)methyl acetates substituted on nitrogen atom of quinolinedione moiety with propargyl group or (1-substituted 1H-1,2,3-triazol-4-yl)methyl group, which are available from the appropriate 3-(4-hydroxymethyl-1H-1,2,3-triazol-1-yl)quinoline-2,4(1H,3H)-diones unsubstituted on quinolone nitrogen atom by the previously described procedures, were deacetylated by acidic ethanolysis. Thus obtained primary alcohols, as well as those aforenamed unsubstituted on quinolone nitrogen atom, were oxidized to aldehydes on the one hand with pyridinium chlorochromate (PCC), on the other hand with manganese dioxide, and to carboxylic acids using Jones reagent in acetone. The structures of all prepared compounds were confirmed by 1H, 13C and 15N NMR spectroscopy. The corresponding resonances were assigned on the basis of the standard 1D and gradient selected 2D NMR experiments (1H–1H gs-COSY, 1H–13C gs-HSQC, 1H–13C gs-HMBC) with 1H–15N gs-HMBC as a practical tool to determine 15N NMR chemical shifts at the natural abundance level of 15N isotope.

The present review gives an overview over the synthesis of organic nitriles and azides through the decarboxylative cyanation and azidation of carboxylic acids, respectively. Mechanistic features of the reactions are considered and discussed in detail.

Size and morphology control during the synthesis of materials requires a molecular-level understanding of how the addition of surface ligands regulates nucleation and growth. In this work, this control is achieved by using three carboxylic acids (tartaric, benzoic, and citric) during sonochemical syntheses. The presence of carboxylic acids affects the kinetics of the nucleation process, alters the growth rate, and governs the size and morphology. Samples synthesized with citric acid revealed excellent photocatalytic activity for the degradation process of Rhodamine B, and recyclability experiments demonstrate that it retains 91% of its photocatalytic activity after four recycles. Scavenger experiments indicate that both the hydroxyl radical and the hole are key species for the success of the transformation. A reaction pathway is proposed that involves a series of dissolution−hydration–dehydration and precipitation processes, mediated by the complexation of Ag+. We believe these studies contribute to a fundamental understanding of the crystallization process and provide guidance as to how carboxylic acids can influence the synthesis of materials with controlled size and morphology, which is promising for multiple other scientific fields, such as sensor and catalysis fields.

At the moment, the most accurate and reliable information about intermolecular interactions in low-molecular compounds and their polymer analogues can be obtained by means of combined UV, visible, and IR spectroscopy. However, this combination is not always used when interpreting the results of intermolecular interactions in carboxylic acids. Therefore, the aim of our study was to investigate the intermolecular interactions in carboxylic acids and their hydration properties using the UV, visible, and IR spectroscopy. The article presents the results of the investigation of intermolecular interactions and hydration in carboxylic acids by means of UV, visible, and IR spectroscopy, and the microscopic study of the swelling/contraction curves of the beads of the sorbents with slightly acidic –СООН groups in exchange reactions of R–COOH + NaOH ↔ R–COO–Na+ + H2O. The study revealed a H-bond in the water dimers formed due to the Coulomb, exchange, charge transfer, polarisation, and dispersion components of the total energy of the hydrogen bonds. In our study we also tested the formulas for the calculation of the energy of the H-bond, enthalpy, the force constants of the Н-bond, and the elongation of the covalent bond. The article suggests a formula for calculating the distance RCH2…O, i.e. the length of the H-bond between the donor and the acceptor of the proton, based on the information about stretching vibrations in the IR spectra of carboxylic acids. We also specified the characteristic frequencies of the stretching and deformation vibrations of certain H-bonds and functional groups in fatty acids. The article demonstrates the possibility of the formation of five- and six-membered cycles, resulting from the formation of Н-bonds between СН2 groups of the chain and –СООН end groups of carboxylic acids. The characteristic electron and vibrational frequencies in the UV and IR spectra were used to determine the intermolecular interactions in ion exchangers CB-2 and CB-4. The microscopic and microphotographic study of the swelling of certain beads of carboxylic cationites helped to register the presence of the outer shell R–COO–…Me+ and the inner shell R-COOH during the exchange reactions: R–COOH + Me+ + OH– ↔ R–COO–…Me+ + H2O.

A new optically active BINOL-amino alcohol has been designed and synthesized in a good yield and applied as chiral nuclear magnetic resonance (NMR) solvating agent for enantioselective recognition. Analysis by 1H NMR spectroscopy demonstrated that it has excellent enantiodifferentiation properties toward carboxylic acids and non-steroidal anti-inflammatory drugs (14 examples). The non-equivalent chemical shifts (up to 0.641 ppm) of various mandelic acids were evaluated by the reliable peak of well-resolved 1H NMR signals. In addition, enantiomeric excesses of the ortho-chloro-mandelic acid with different enantiomeric ratio were calculated based on integration of proton well-separated splitting signals.

The pKa values of twelve β-hydroxy-β-arylalkanoic acids and ibuprofen were determined using a modified RP-HPLC method. The stationary phase was octadecyl modified (C-18) silica gel, and the mobile phases were mixtures of methanol and one of ten different buffers (60:40 volume ratio). The mean retention time of each compound was plotted against the pH of each of the ten used mobile phases. The inflection point of the obtained sigmoidal curve represents the s w pKa of a compound. Using s w pKa in previously established equations for the specific methanol/buffer mixture, the w w pKa values (in pure water) were calculated. The obtained w w pKa values for the synthesized compounds were in a range from 3.40 to 3.74, and the w w pKa for ibuprofen was 4.27. The Predicted pKa values for this type of compounds in the MarvinSketch 5.11.5. Program were in poor correlation with the experimental results, while in ACD/ /I-Labs pKa values were calculated as a wide range. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172041]